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Medina, Dayana

From: Feldman, Michael

Sent: Tuesday, February 26, 2013 12:04 PM

To: Pettyjohn, Mary; Medina, Dayana

Cc: Donaldson, Guy; Snyder, Erik; Jeremy Jewell (jjewell@trinityconsultants.com)

Subject: RE: FW: Region 6 comments on AEP Flint Creek updated BART report

Mary,

In response to Trinity’s questions below regarding the calculation of PM and SO4 emissions to be modeled:

Calculation of Total PM10 emissions:

Total PM10 emissions should be estimated based on current PM emissions and the anticipated control efficiency or

vendor guarantee of the proposed control equipment.  The appropriate NPS worksheet and coal characteristics should

be utilized to determine speciation (PMC, PMF, EC and SOA) given the total PM10 emissions (or filterable PM10).  We

note that if AEP/SWEPCO upgrades the PM controls, the PM emission limit should be adjusted accordingly.      

Calculation of SO4 emissions:

Rather than assuming that 100% of inorganic condensable PM is SO4, the EPRI method estimates the amount of SO2

that is oxidized to SO3 and then assumes that 100% of SO3 is converted to H2SO4.  This methodology also accounts for

loss of sulfuric acid due to downstream equipment, such as the air pre‐heater, ESP or FF, and scrubber.    

Please contact me if you have any questions concerning these emission calculations.

Thank you,

Michael Feldman, PhD 

Environmental Engineer 

Air Planning Section 

U.S. EPA Region 6, 6PD-L 

Phone: 214-665-9793 

feldman.michael@epa.gov

   

From: Pettyjohn, Mary [mailto:PETTYJOHN@adeq.state.ar.us] 

Sent: Friday, February 22, 2013 8:49 AM 

To: Medina, Dayana 

Cc: Donaldson, Guy; Snyder, Erik; Feldman, Michael; Jeremy Jewell (jjewell@trinityconsultants.com) 

Subject: FW: FW: Region 6 comments on AEP Flint Creek updated BART report 

Good morning,

Listed below are Trinity’s questions on EPA’s comment on recalculating AEP’s SO4 rates.

Please respond as soon as possible.

Thank you,

Mary

From: Jeremy Jewell [mailto:JJewell@trinityconsultants.com] 

Sent: Friday, February 22, 2013 8:09 AM 

To: Pettyjohn, Mary 

Subject: Re: FW: Region 6 comments on AEP Flint Creek updated BART report 
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Mary, 

I have a question about the "Modeling and Emission Estimates" comment regarding recalculating the SO4 rates. Can you 

forward this to EPA? 

Using the referenced EPRI approach gives significantly lower SO4 emission rates in both the baseline and post-control 

scenarios. This being the case, what is EPA's preferred method for revising the model input emission rates? Should the 

assumption that all inorganic PM is SO4 be maintained? If so, should the PM species percentages from the NPS 

spreadsheets be adjusted to account for the lower inorganic rates (so as to maintain the same total PM emission 

rate)? This will result in higher relative amounts for all PM species except inorganic PM. 

Thanks, 

_________________________________________________________________ Jeremy W. Jewell, Principal and Manager of Consulting Services for Oklahoma NEW OKLAHOMA CITY ADDRESS AND PHONE NUMBER 201 NW 63rd St., Suite 220 Oklahoma City, OK 73116 | 405-848-3724 1831 E. 71st Street Tulsa, OK 74136 | 918-877-2742 e-mail: jjewell@trinityconsultants.com | e-fax: 918-512-7084 

FW: Region 6 comments on AEP Flint Creek updated BART report

"Pettyjohn, Mary" <PETTYJOHN@adeq.state.ar.us> 02/13/2013 03:05 PM

To: "Brian Bond (tbbond@aep.com)" <tbbond@aep.com>, "Kris Gaus (kpgaus@aep.com)" <kpgaus@aep.com>, "Jeremy Jewell 

(jjewell@trinityconsultants.com)" <jjewell@trinityconsultants.com>

Cc: 

Bcc: 

Client: AEP - Flint Creek, AR 123701.0038, 113701.0022

Category: 

General

Here are EPA’s comments on the updated analysis.

 

Please let me know if you would like to discuss these comments with us and EPA. 

 

Best wishes, 

Mary 

 

 

 

From: Medina.Dayana@epamail.epa.gov [mailto:Medina.Dayana@epamail.epa.gov] 

Sent: Friday, February 08, 2013 1:06 PM

To: Pettyjohn, Mary

Cc: Feldman.Michael@epamail.epa.gov; Donaldson.Guy@epamail.epa.gov

Subject: Region 6 comments on AEP Flint Creek updated BART report 

 

Hi Mary, 

Thank you for the opportunity to comment on the updated draft BART report for AEP Flint Creek. Here are Region 6's 

comments, which we'd be happy to discuss with you. 

Comments on the AEP/SWEPCO Flint Creek January 2013 BART Analysis: 

SO2 Control Efficiency 
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For NID, AEP/SWEPCO assumes a control efficiency of 92%, resulting in a controlled emission rate of 0.06 

lbs/MMBtu. However, testimony of Mr. Christian T. Beam of AEP (attached below) before the Arkansas PUC, 2-8-12, 

page 22, indicates that for the NID system proposed for Flint Creek, "NID technology can attain higher levels of SO2 

reduction, with vendor guarantee removal rates of 98% compared to maximum removal rates of 95% for SDA and other 

DFGD technologies. The higher removal rate for NID allows for greater fuel flexibility for the Flint Creek site to meet 

environmental compliance limits." We have seen literature from the NID vendor that substantiates a 98% removal 

efficiency. A BART evaluation requires that, "in analyzing the technology you take into account the most stringent 

emission control level that the technology is capable of achieving." (70 FR 39166). Therefore, AEP/SWEPCO should 

demonstrate this requirement has been met. 

We further note that AEP/SWEPCO has provided little documentation for the capital and operating costs it presents for 

the various SO2 BART control options, while selecting the less stringent control option. It is also unclear why in the 

January 2013 BART report, the estimated capital cost in AEP’s cost analysis for the NID system was increased by more 

than $118 million when compared to the estimated cost in the September 2012 version of the BART report. 

Modeling and Emission Estimates: 

To estimate sulfuric acid emissions to model for the baseline and control cases, all inorganic PM was assumed to be 

SO4. This assumption and assumptions of SO4 reductions due to controls impacts the baseline modeling as well as the 

visibility benefit from WFGD when compared to NID. We recommend that sulfuric acid emissions from power plants are 

calculated by estimating the amount of H2SO4 produced and the amount of H2SO4 removed by control equipment using 

information from the Electric Power Research Institute (EPRI) Estimating Total Sulfuric Acid Emissions from Stationary 

Power Plants: Version 2010a. EPRI,

Palo Alto, CA: 2010. 1020636. consistent with the methodology detailed in the Technical support document that 

accompanies the Oklahoma FIP. These calculations rely on assumed values for the amount of fuel sulfur converted to 

SO2, the amount of SO2 oxidized to SO3, and the amount of H2SO4 lost to (or mitigated by) the air pre-heater and 

applicable control equipment, such as baghouses, and FGDs. 

It is also unclear how total PM10 emission rates were determined for the NID and WFGD control cases. The modeled 

PM10 emission rates for NID and WFGD are approximately 0.002lb/MMBtu and 0.0125 lb/MMBtu. 

Furthermore, there is an error in the PM speciation calculation obtained by using the NPS spreadsheets. Emission factors 

within these tables vary by the type of emission control equipment downstream and are functions of the coal’s sulfur and 

ash content. It appears that calculated PM speciation used the placeholder values present in the worksheets, rather than 

inputting specific data for the type of coal used as given in footnote 8 on page 4-1 of the BART analysis. The PM 

speciation worksheets for the controlled cases should be provided in addition to the corrected basecase worksheet. 

NOx BART: 

For NOx BART, AEP/SWEPCO assumes an emission rate of 0.23 lbs/MMBtu, using LNB/OFA, in the event CAIR cannot 

be relied upon. However, the same testimony referenced above states, "If low NOX burners and over-fire air are installed 

on Flint Creek, the NOx rate is expected to drop to the 0.18 to 0.22 lbs/mmbtu range." A similar claim is made on page 6-

4 of the BART report. As above, AEP/SWEPCO should demonstrate that the most stringent emission control level for this 

technology is analyzed. 

We further note that AEP/SWEPCO has provided little documentation for the capital and operating costs it presents for 

the various NOx BART control options. 

PM BART:

EPA approved the current ESP as BART for PM. IF AEP/SWEPCO upgrades the PM controls, the PM emission limit 

should be adjusted accordingly. 

Thank you, 

Dayana Medina 

U.S. Environmental Protection Agency, Region 6 
4

Multimedia Planning and Permitting Division 

Air Planning Section (6PD-L) 

1445 Ross Avenue 

Dallas, TX 75202 

214-665-7241

medina.dayana@epa.gov 

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